Aphonopelma is a genus of tarantulas, members of which are native to the Americas. It includes nearly all of the North American tarantulas north of Mexico and a considerable part of the tarantulas which range into Central America. Only a few species are described from South America. About 90 species have been described, but many, if not most, of these are inadequately studied and very little is known about them. Most are large and, like other New World tarantulas, they have urticating hairs. Most are docile in captivity. The taxonomy is poorly understood and species are difficult to tell apart, especially those that are brown or black without other pattern. In captivity they will eat crickets, in the wild they will eat most smaller insects. Most species found in the Southwestern United States have an adult leg span of 4.5 inches (11.5 cm), though some Arizona species have been known, on occasion, to just barely exceed 6 inches (16 cm).